Kohler LH630-775 Service Manual page 94

Eyelet Terminal for Ignition
Key Switch (or Starter Post)
Ignition Module Input
B+ and
Carburetor
Solenoid
Input
Oil Pressure Safety Input
Figure 8-4. Electronic CD Ignition System (For Customer Connected Tractor Applications).
L1
Figure 8-5. Capacitive Discharge Ignition Module.
Operation: As the flywheel rotates, the magnet
grouping passes the input coil (L1). The
corresponding magnetic field induces energy into the
input coil (L1). The resultant pulse is rectified by D1
and charges capacitor C1. As the magnet assembly
completes its pass, it activates the triggering device
(L2), which causes the semiconductor switch (SCS) to
turn on. With the device switch "ON," the charging
capacitor (C1) is directly connected across the
primary (P) of the output transformer (T1). As the
capacitor discharges, the current initiates a fast rising
flux field in the transformer core. A high voltage pulse
is generated from this action into the secondary
winding of the transformer. This pulse is delivered to
the spark plug gap. Ionization of the gap occurs,
resulting in an arc at the plug electrodes. This spark
ignites the fuel-air mixture in the combustion
chamber.
Diodes
Red
Violet
Rectifier-Regulator
D1
SCS
L2
Troubleshooting CD Ignition Systems
The CD ignition systems are designed to be trouble
free for the life of the engine. Other than periodically
checking/replacing the spark plugs, no maintenance
or timing adjustments are necessary or possible.
Mechanical systems do occasionally fail or break
down however, so the following troubleshooting
information is provided to help you get to the root of
a reported problem.
The CD ignition systems produce a high energy electric spark,
but the spark must be discharged, or damage to the system can
result. Do not crank or run an engine with a spark plug lead
disconnected. Always provide a path for the spark to discharge
to ground.
Electrical System and Components
Carburetor Solenoid
Red
Green
Ignition Modules
White
B+
White
C1
T1
S
P
CAUTION: High Energy Electric Spark!
Section 8
Oil Pressure
Safety
Spark
Plugs
Flywheel/Stator
Spark
Plug
8
8.5